KR102387217B1 - Aqueous alkyd dispersion with improved application performance in terms of resistance to blocking and yellowing, hardness development and gloss - Google Patents

Abstract

The present invention relates to an aqueous alkyd resin dispersion, which comprises in its fatty acid component a1) at least one polyunsaturated fatty monoacid a11) having at least two unsaturations per molecule and a monoacid a111) having at least 35% by weight of conjugated unsaturation ), wherein the weight ratio of the fatty monoacid a111) to the alkyd resin is 5% or more, preferably 5-40%, more preferably 5-35% short oil alkyd resin, and b ) at least one anionic phosphate surfactant. The present invention also encompasses a process for its preparation and its use in decorative coatings. Coatings made from these aqueous dispersions have improved performance in terms of resistance to blocking and yellowing, hardness development and gloss.

Description

Aqueous alkyd dispersion with improved application performance in terms of resistance to blocking and yellowing, hardness development and gloss

The present invention also relates to alkyd emulsions, referred to herein as alkyd dispersions, which for the obtained coatings have improved application performance qualities compared to commercial alkyd emulsions used as reference.

More particularly, the present invention relates to a reference emulsion at 50° C. while improving the performance quality in terms of resistance to blocking, resistance to yellowing, hardness development and gloss of said emulsion according to the present invention, compared to a reference emulsion. It aims to provide stability upon storage for one month.

The present invention relates firstly to aqueous dispersions of alkyd resins based on fatty acids having conjugated unsaturation and specific surfactants having specific application performance qualities in terms of resistance to blocking and yellowing, hardness development and gloss, and then to obtain such dispersions It relates to certain methods and in particular to aqueous coating compositions, more particularly to their use as binders in aqueous decorative coating compositions.

The technical problem to be solved by the present invention compared to the prior art is, as explained above, a coating obtained from an aqueous dispersion of an alkyd resin having a specific conjugated unsaturation and prepared in the presence of a specific surfactant. It is to find a difficult compromise of performance quality, which consists in improving the resistance to yellowing of water, resistance to blocking, hardness development during drying and gloss, which without compromising its stability in storage, in particular 50 at °C, while providing stability upon storage for 1 month.

By the specific choice of the content of specific conjugated unsaturation of the resin and the use of specific phosphate surfactants, more particularly phosphate surfactants, especially phosphate esters, including phosphate monoesters and diesters of specific alcohols, the present invention has the disadvantages of the prior art ( It overcomes the above-mentioned demand for improvement) and makes it possible to obtain aqueous dispersions of alkyd resins having the aforementioned improved performance qualities.

Accordingly, the subject of the present invention relates first to an aqueous dispersion of at least one alkyd resin obtained in the presence of certain phosphate surfactants.

A second subject of the present invention relates to a specific process for the preparation of said aqueous dispersions of the alkyd resins of the present invention.

Aqueous coating compositions comprising at least one aqueous dispersion of an alkyd resin according to the invention also belong to the invention.

Another subject of the invention is the use of the aqueous dispersions of the invention as binders for aqueous coating compositions, preferably aqueous decorative coating compositions, in particular for aqueous paint, varnish or stain compositions.

Finally, a final subject of the invention relates to coatings derived from at least one aqueous dispersion of an alkyd resin according to the invention or obtained by a process according to the invention.

Accordingly, a first subject of the present invention relates to an aqueous dispersion of an alkyd resin comprising:

a) having a Noury viscosity at 110° C. according to the AFNOR XPT51213 method in the range from 7000 to 13 000 mPa.s, preferably from 9000 to 12 000 mPa.s, and having, in the fatty acid component a1) thereof, at least two unsaturations per molecule, A short oil alkyd resin comprising at least one polyunsaturated fatty monoacid a11) having a monoacid a111) (conjugated monoacid) having a conjugated unsaturation of at least 35%, preferably at least 42% by weight , with respect to the alkyd resin, the content of the fatty monoacid a111) by weight is 5% or more, preferably 5% to 40%, more preferably 5% to 35%, short oil alkyd resin,

b) at least one anionic phosphate surfactant, in particular a phosphate alkyl alkoxy ester, wherein said surfactant b) is more particularly a mixture of phosphate monoesters and diesters, the alkyl group being a C ₁₀ -C ₁₆ alkyl group, 4 to 10 alkoxylated with alkoxy units, said alkoxy units preferably selected from ethoxy and/or propoxy units, more preferably ethoxy units.

In the present invention, "short oil alkyd" resin means an alkyd resin having a content by weight of unsaturated fatty acids (as triglyceride equivalent) of less than 45%.

Preferably, the alkyd resin a) has, among polystyrene equivalents, a number-average molecular weight Mn measured by GPC in THF in the range of 2500 to 6000, more preferably 3500 to 5000.

In the present invention, according to a preferred form of the dispersion, the fatty monoacid a11) is a dehydration product of castor oil.

As suitable examples of polyunsaturated fatty monoacids a11) comprising conjugated monoacids according to a111), Nouracid® ^DE656 , DE655, DE554, DE503, DZ453 (dehydrated castor fatty acid - Oleon), Nouracid® ^HE456 , HE305, HE304 (isomer) Nitrated sunflower fatty acids - Oleon), Nouracid ^® LE805 (isomerized linseed fatty acids - Oleon), Dedico ^® 5981 (dehydrated castor fatty acids - Croda), Isomergin ^® SK, SY, SF (isomerized vegetable fatty acids - Hobum Harburger Fettchemie Brinckman & Mergell GmbH), Pamolyn ^® 300, 380 (isomerized linoleic acid - Eastman), preferably dehydrated castor oil fatty acids.

According to another specific form of the dispersion of the present invention, the acid number of the alkyd resin is less than 25 mg KOH/g, preferably less than 15 mg KOH/g, more preferably less than 12 mg KOH/g.

More particularly, said surfactant b) is a phosphate ester of a C ₁₀ to C ₁₆ alcohol which is alkoxylated with 4 to 10 ethoxy units, preferably 4 to 8 ethoxy units.

According to a particular form, said surfactants b) comprise phosphate diesters of said alcohols, preferably phosphate diesters and phosphate monoesters (mixtures of phosphate monoesters and phosphate diesters).

According to another specific and preferred form, said surfactant b) is a mixture of phosphate monoester and phosphate diester, wherein the weight ratio of phosphate monoester to phosphate diester is from 0.8 to 12. In the present case, more particularly, the alcohol is a C ₁₂ to C ₁₄ alcohol, preferably a C ₁₃ alcohol. More preferably, the number of the alkoxy units is 4 to 8, preferably 6, and more preferably, the unit is an ethoxy unit.

The C ₁₀ to C ₁₆ alcohols are preferably aliphatic and may be linear or branched.

The content by weight of the surfactant b) with respect to the dispersion is from 1% to 3% by weight, preferably from 1.5% to 2.5% by weight, more preferably from 1.8% to 2.2% by weight relative to the dispersion. can be variable.

The content by weight of the alkyd resin a) in the dispersion may vary from 35% to 65%, preferably from 40% to 60%, more preferably from 45% to 55%.

According to another more particularly preferred form, said dispersion of the invention comprises, in addition to said surfactant b), a ratio selected from non-ionic surfactants, preferably polymeric non-ionic surfactants, which are oligomers. - a surfactant c) selected from ionic surfactants, in which case the weight ratio of anionic surfactant b) to non-ionic surfactant c), b)/c) is 1 to 3 , preferably in the range from 1.5 to 2.5.

As preferred examples of non-ionic surfactants suitable as surfactant c) the following may be mentioned: ethoxylated (2 to 35 EO) C ₁₂ -C ₁₈ fatty alcohols, propoxylated/ethoxylated C ₄ -C ₈ alcohol (where propoxy/ethoxy weight ratio is approximately 1), ethoxylated (2-40 EO) iso-C ₁₀ fatty alcohol, ethoxylated (2-40 EO) monobranched C ₁₀ -C ₁₈ fat Alcohol, C ₁₈ Sorbitol Ester, Ethoxylated (5-20 EO Units) Sorbitol Ester or Ethoxylated (7-100 EO) C ₁₂ -C ₁₈ Fatty Acid, Ethoxylated (30-40 EO) Castor Oil, Ethoxylated (7-60 EO) hydrogenated castor oil, fatty esters such as: glyceryl palmitate, glyceryl stearate, ethylene glycol stearate, diethylene glycol stearate, propylene glycol stearate, polyethylene glycol 200 stearate (Mn = 200 PEG) or ethoxylated (2-15 EO) C ₁₈ fatty esters.

The content of surfactants of type c) can vary from 0.1% to 1% by weight relative to the dispersion.

According to another possible form of the alkyd resin dispersion, the resin comprises, in its acid component A), at least one aromatic dicarboxylic acid or anhydride a2) and optionally an aromatic monocarboxylic acid a3) and its alcohol component B) to polyols b1) having a functionality in the range of 3 to 6, preferably 4. More preferably, the polyol is aliphatic.

As suitable examples of an aromatic polycarboxylic acid or anhydride a2) having an intermediate mean functionality of 2 to 4 (which can be obtained by mixing two or more polyacids), the following acids or anhydrides are Mention may be made: for products of functionality 2: terephthalic acid, isophthalic acid or phthalic acid, for products of functionality 3: trimellitic acid and anhydride, and for products of functionality 4: pyromellitic anhydride.

As suitable examples of the aromatic monocarboxylic acid a3), mention may be made of benzoic acid and p-(tert-butyl)benzoic acid.

As suitable examples of polyols b1) having a functionality in the range from 3 to 6, mention may be made of the following polyols (by functionality):

- trifunctional (triol): trimethylolpropane, glycerol or trimethylolethane, preferably trimethylolpropane,

- tetrafunctional (tetrols): ditrimethylolpropane ether or pentaerythritol, preferably pentaerythritol,

- penta- and hexa-functional: dipentaerythritol (6), polyglycerol (5-6) and sorbitol (6).

According to another option of the dispersion according to the invention, the alkyd resin additionally has in its fatty acid component a1) at least two unsaturations per molecule, preferably soybean oil, sunflower oil or tall oil (TOFA: tall oil fatty acid) ) at least 90% by weight of at least one other polyunsaturated fatty monoacid a12) comprising at least 90% by weight of non-conjugated polyunsaturated monoacid a121). According to a particular option, the alkyd comprises, in its fatty acid component a1) only monoacids a11) as defined above.

A second subject of the invention relates to a process for the preparation of an aqueous dispersion according to the invention, as described above, comprising the following successive steps:

i) the preparation of said alkyd resin a) in bulk,

ii) melting of the resin a);

iii) adding said surfactant b) and optionally said non-ionic surfactant c), as defined above,

iv) partial addition of water;

after,

v) neutralization of the acidity of a) and b) with a base, said base preferably selected from LiOH, KOH, NaOH, NH ₄ OH and tertiary amines,

vi) emulsification by phase inversion and control of the solids content after emulsification.

As an example of a tertiary amine, triethylamine may be mentioned.

More particularly, in the method, steps ii) and iii) at a temperature in the range from 80 to 100° C., step iv) at a temperature in the range from 80 to 65° C., step v) at a temperature in the range from 60 to 70° C., vi) is carried out at a temperature in the range from 55 to 65 °C.

The aqueous dispersions of the present invention preferably have an average particle size in the range of 50 to 500 nm, preferably in the range of 100 to 300 nm (by laser particle sizing), and a solids content of 35% to 65%, preferably 40%. to 60%, more preferably 45% to 55%.

The solids content is determined by the ISO 3251 method.

The alkyd resin according to the present invention may have an OH number ranging from 20 to 150 mg KOH/g, preferably from 30 to 100 mg KOH/g, and an average functionality f ranging from 1.9 to 2.1. This average functionality is defined according to the following relation:

f = 2 ∑ _i n _i fi / ∑ _i n _i

[wherein, each of n _i and fi is the number of moles and functionality of the acid or alcohol component i (average over all reactive acid and alcohol components)].

Another subject according to the invention relates to a coating composition comprising at least one aqueous dispersion as defined above according to the invention, comprising a dispersion obtained by the method as defined above.

More particularly, the composition is an aqueous decorative coating composition, in particular an aqueous paint, varnish or stain composition, more particularly an aqueous paint composition.

Even more particularly, the coating composition comprises an aqueous decorative coating composition, more preferably a paint, varnish or stain, even more preferably a finishing paint, varnish or stain, more particularly an interior or exterior finishing paint for wood, metal, wall or plastic. , an aqueous decorative coating composition for varnishes or stains.

Another subject of the invention is an aqueous coating composition, preferably an aqueous decorative coating composition, more preferably a paint, varnish or stain, even more preferably a finishing paint, varnish or stain, more particularly for wood, metal, wall or plastic. It relates to the use of the aqueous dispersions of the present invention as defined above, including the dispersions obtained by the process as defined above, as aqueous binders for aqueous coating compositions for internal or external finishing paints, varnishes or stains for use.

Even more particularly, the use is, for PVC (pigment volume concentration) of 18% and iron-based desiccant, a resistance to blocking of less than 2 according to the method described in 8) of "Tests and methods used" of the detailed description , Persoz hardness development after 14 days of at least 100 s according to ISO 1522 method, and resistance to yellowing after 1 month exposure at ambient temperature of less than 2 according to ASTM 31396, and greater than 93% (dry) according to ISO 2813 method It relates to a paint with a 20° gloss after 24 h.

Finally, the present invention relates to coatings, preferably paints, derived from the use of at least one aqueous dispersion of the invention as defined above or at least one aqueous dispersion obtained by a process as defined according to the invention above. , varnish or stain coatings.

The following examples illustrate the invention and its performance qualities, and do not limit its scope in any way.

experimental part

1) Starting material (see Table 1 below)

Table 1

2) Example

2.1) Synthesis of alkyd A for dispersion B according to the invention

Example 1

285 g of soy fatty acid (SOFA) and 95 g of Nouracid® DE656, 265.9 g of pentaerythritol, 287.1 g of phthalic anhydride and 166.3 g of benzoic acid are charged to a 1.5 liter reactor comprising:

- dip pipe for nitrogen addition,

- temperature probe,

- reflux condenser supplying water at 12℃,

- a round bottom flask for recovering the water derived from the esterification reaction.

While bubbling nitrogen, the combined mixture is brought to 240° C. using an electric heating mantle, and the formed water is distilled off as formed until an acid number of less than 12 is obtained. At the end point of the synthesis, a viscous alkyd resin A is obtained, which exhibits the following characteristics:

- Acid number: 11.5 mg KOH/g

- Solids content: 100%

- Noury viscosity at 110°C according to AFNOR XPT 51213 method: 110 000 mPa.s

2.2) Dispersion of alkyd A to obtain dispersion B according to the invention

Example 2

477.1 g of alkyd resin A obtained according to the operating conditions of Example 1 described above, pre-melted at 80-100° C., were introduced into a 1 liter reactor. When the temperature of the reactor is stabilized at 85° C., two surfactants are introduced: a phosphate surfactant (19.7 g) and a non-ionic surfactant (which is an ethoxylated/propoxylated C ₄ -C ₈ alcohol (9.7 g) ) lim).

The mixture is stirred for 30 minutes. Thereafter, 112 g of water are introduced over 30 minutes and the reactor is cooled to 65°C. Then, 55.3 g of 10% LiOH are introduced over 30 minutes to neutralize the alkyd and phosphate surfactants. While the mixture is cooled to 60° C., it is stirred for 30 minutes. Finally, while maintaining the temperature at 60° C., 345 g of water are introduced over 2 hours. The reactor is then cooled to ambient temperature and the solids content is adjusted to 50%.

At the end point, emulsion B is obtained, which exhibits the following characteristics:

- Solids content: 50%

- pH: 7.5

- Brookfield viscosity at 23°C: < 100 mPa.s

- particle size: < 200 nm

In comparison with the reference commercial product (Synaqua ^® 4804 from Arkema), the stability upon storage at 50° C. for 1 month with or without modification of the solid content of the emulsion B according to the invention is presented in Table 2 below.

Stability upon storage at 50° C. consists of measuring the solids content at the surface of the sample and comparing it with the solids content measured at the bottom of the sample. Stability is considered good if the difference in the measured solid content is 2% or less after storage at 50° C. for 1 month.

Table 2

The yellowing of the alkyd emulsion B according to the invention is also compared with Synaqua ^® 4804. The obtained results are summarized in Table 3 below.

Table 3

A compared alkyd emulsion was formulated as a gloss paint with an iron-based desiccant having a pigment volume concentration (PVC) of 18% and an iron-based desiccant having a TiO ₂ content of 24%.

formulation used (See Table 4 below)

Table 4

The calculated characteristics of the first formulation (without desiccant) :

- PVC = 18.2%

- solids content by weight = approx. 54%

- solids content by volume = approximately 41%

The performance qualities in terms of resistance to yellowing, hardness development, resistance to blocking and gloss of the formulations of the dispersions according to the invention are compared with those of Synaqua ^® 4804 in Table 5 below.

Table 5

Tests and Methods Used

These tests and methods are generally valid for the features mentioned in the detailed description, especially in the examples presented.

1) Solid content :

Evaluation according to ISO 3251 according to conditions: 1 g of dispersion for 1 hour at 125° C. and the results are expressed in %.

2) Viscosity :

Estimation of Noury viscosity at 110° C. for bulk resins according to standard AFNOR XPT 51213 and expressed in mPa.s.

Brookfield viscosity evaluation at 23°C, 10 rpm, using 2 and 3 spindles on a Brookfield RVDVE-230 viscometer according to standard ISO 2555.

3) particle size :

The size of the particles is measured using an apparatus of the type Zetasizer-Malvern Instruments Ltd. Dilute the dispersion sample in a clear cell with filtered demineralized water and measure the size of the particles by 90° laser scattering.

4) Acid number and hydroxyl number :

The acid number is evaluated according to the standard ISO 3682.

The hydroxyl number is evaluated according to standard NFT 30-403.

5) Hardness :

According to the standard ISO 1522, for films with a wet thickness of 100 μm applied to glass sheets after different drying times, the hardness is evaluated using a Persoz hardness pendulum.

6) Yellowing :

"Dr Lange" Micro Color LMC Spectrocolorimeter type device.

Determination of yellowing index Yi according to standard ASTM 313-96 for dry films at different drying times.

Films with a wet thickness of 150 μm are applied to the Leneta chart using a Bird film applicator.

7) Gloss :

According to standard ISO 2813, measurements are carried out using a BYK Gardner GmbH micro-TRI-gloss glossmeter at 20° for wet films with a thickness of 200 μm deposited on glass sheets, after different drying times.

8) Resistance to blocking :

Using a film applicator, the paint to be evaluated is applied to two Leneta 2A charts at selected thicknesses. This paint is stored in a climate-controlled chamber (at 23° C.±1° C. and 50%±5% RH) for a pre-measured time. The painted side of this chart is then placed oppositely between two sheets of glass. The assembly is compressed by weight so that a pressure of 50 g/cm 2 can be obtained over the entire test surface. The painted side remains in contact in a climate-controlled chamber for a pre-measured time period. At the end of the contact time, the charts are gently separated by pulling the two charts in all directions.

The damage caused on the paint film is then quantified on a scale ranging from 0 to 8 according to the guidelines given in the table below (0 indicates best performance, 8 indicates worst performance):

Evaluation scale of resistance to blocking

Claims (20)

An aqueous alkyd resin dispersion comprising:
a) a Noury viscosity at 110° C. according to AFNOR XPT 51213 in the range from 7000 to 13 000 mPa.s, wherein in the fatty acid component a1) thereof, having at least two unsaturations per molecule and having a content by weight of at least 35% conjugated unsaturation A short oil alkyd resin comprising at least one polyunsaturated fatty monoacid a11) having a monoacid a111) having, with respect to the alkyd resin, the content by weight of the fatty monoacid a111) is 5% to 40 % phosphorus short oil alkyd resin,
b) at least one anionic phosphate surfactant which is a phosphate alkyl alkoxy ester;
An aqueous alkyd resin dispersion, wherein said surfactant b) is a mixture of phosphate monoester and phosphate diester, wherein the weight ratio of phosphate monoester to phosphate diester is from 0.8 to 1.2. The aqueous alkyd resin dispersion according to claim 1, wherein the fatty monoacid a11) is a dehydration product of castor oil. The aqueous alkyd resin dispersion of claim 1 , wherein the resin has an acid number of less than 25 mg KOH/g. The aqueous alkyd resin dispersion according to claim 1, wherein the surfactant b) is a phosphate ester of a C ₁₀ to C ₁₆ alcohol alkoxylated with 4 to 10 ethoxy units. delete delete The aqueous alkyd resin dispersion according to claim 4, wherein the alcohol is a C ₁₂ to C ₁₄ alcohol. 8. The method according to claim 7, wherein the number of alkoxy units is 4 to 8; Aqueous alkyd resin dispersion. 2. The method according to claim 1, wherein the content by weight of the surfactant b) to the dispersion varies from 1% to 3%. Aqueous alkyd resin dispersion. 2. The method according to claim 1, wherein the content by weight of the alkyd resin a) to the dispersion varies from 35% to 65%. Aqueous alkyd resin dispersion. The non-ionic surfactant according to claim 1, wherein said dispersion comprises, in addition to said surfactant b), a surfactant c) selected from non-ionic surfactants selected from polymeric non-ionic surfactants. wherein the weight ratio of anionic surfactant b) to active agent c), b)/c) ranges from 1 to 3, Aqueous alkyd resin dispersion. The polyol b1) according to claim 1, wherein the resin comprises, in its acid component A, at least one aromatic dicarboxylic acid or anhydride a2), and in its alcohol component B, a polyol b1) having a functionality in the range of 3 to 6 containing, Aqueous alkyd resin dispersion. 2. The alkyd resin according to claim 1, wherein said alkyd resin additionally comprises, in its fatty acid component a1), at least 90% by weight of non-conjugated polyunsaturated monoacid a121) having at least two unsaturations per molecule. Conjugated polyunsaturated fatty monoacid a12) comprising Aqueous alkyd resin dispersion. A process for preparing an aqueous dispersion of claim 1 comprising the following successive steps:
i) the preparation of said alkyd resin a) in bulk,
ii) melting of the resin a);
iii) adding said surfactant b);
iv) partial addition of water;
after,
v) neutralization of the acidity of a) and b) with a base selected from LiOH, KOH, NaOH, NH ₄ OH and tertiary amines,
vi) emulsification by phase inversion and control of the solids content after emulsification. 15. The method according to claim 14, wherein steps ii) and iii) are carried out at a temperature in the range from 80 to 100 °C, step iv) is carried out at a temperature in the range from 80 to 65 °C, and step v) is carried out at a temperature in the range from 60 to 70 °C. wherein step vi) is carried out at a temperature in the range of 55 to 65 °C. A coating composition comprising the aqueous dispersion of claim 1 or the dispersion obtained by the method of claim 14 . 17. The coating composition of claim 16, which is an aqueous decorative coating composition. A process for producing an aqueous coating composition comprising using the aqueous dispersion of claim 1 or the dispersion obtained by the method of claim 14 as an aqueous binder for an aqueous coating composition which is an aqueous decorative coating composition. 19. The method according to claim 18, for a PVC (pigment volume concentration) of 18% and an iron-based desiccant for blocking of less than 2 according to the method described in 8) of "Tests and methods used" of the detailed description. Resistance, Persoz hardness development after 14 days of at least 100 s according to ISO 1522 method, and resistance to yellowing after 1 month exposure at ambient temperature of less than 2 according to ASTM 31396, and greater than 93% 24 h according to ISO 2813 method A method for producing a paint having a post 20° gloss. A coating resulting from the use of an aqueous dispersion according to claim 1 or an aqueous dispersion obtained by the process according to claim 14 .